CONWAY — A group of former law enforcement agents and missing persons' specialists converged at the Cranmore Mountain base camp over the weekend, joining the search for 15-year-old Abigail Hernandez.

Twelve dog teams with 60 volunteer searchers arrived Friday from The Mission for the Missing, a Boston-based non-profit group created in 2009 that works independently or in conjunction with law enforcement with the mission of bringing loved ones home, according to the group's leader, Alan Tate.

They were searching for personal items that her mother said she likely had with her when she disappeared: an oversized camouflage-colored book bag, a cream-colored purse, and a silver-colored necklace with a heart-shaped pendant that has a blue stone in it.

They searched places that might not have been covered by other law enforcement agencies looking for the teen last seen Oct. 9 — Echo Lake State Park, the Kancamagus Highway, West Side Road, and areas around the Saco River.

After three days of searching, the group packed up and left the area Sunday, having found nothing to help the investigation, Tate said.

But Tate left behind a message of hope. "Our motto is 'we never give up,' and these people have no reason to give up now," he said.

"There are so many possible reasons to explain why she hasn't been found yet," Tate said. "Sometimes kids this age have psychological issues. Sometimes they need some time away. Sometimes they are abducted, but sometimes they've just run away with friends somewhere."

Tate said he met with Zanya Hernandez, Abigail's mother, for three hours on Thursday, adding details to the police reports the group had already been given.

Tate's teams, made up of search teams from New Hampshire, Massachusetts, Connecticut and Rhode Island, also covered areas around the North-South Road and Pudding Pond, along the route the girl was believed to have been walking the day she left Kennett High School.